1. Field of the Invention
The present invention relates to apparatus for separating undesired metallic and other heavy particulates from a mixture of particulate materials containing aluminum alloy particles. More particularly, the present invention relates to apparatus for separating particles of lead, brass, copper, and other relatively heavy materials from a particulate stream that includes shredded used aluminum alloy beverage containers.
2. Description of the Related Art
The recycling of aluminum alloy used beverage containers (UBC) has been encouraged for some time as a way of reusing previously processed aluminum and thereby helping to conserve a substantial quantity of the energy that would otherwise be needed to obtain usable aluminum from bauxite. Recycling of UBC also helps to preserve the environment by encouraging the collection of UBC and thereby removing them from streets, roadways, and other public places.
In order to encourage the collection of UBC for recycling, the promoters of recycling efforts, of which the aluminum producers themselves are in the forefront, frequently provide financial incentives in the form of cash payments to those who collect and return UBC to a recycling center. The payments made to those who present recyclable UBC-containing material are based upon the weight of such material that is presented for recycling. However, in addition to including UBC, the material offered for recycling very often contains other, undesirable, ferrous and non-ferrous metals and other relatively heavy materials that are not desired in aluminum to be remelted.
Among the undesirable materials present in materials presented for recycling is lead. Although lead is sometimes present in very small amounts in aluminum in alloyed form, oftentimes, however, free lead has been either inadvertently or intentionally included in the UBC offered for recycling. Free lead can be present in many different forms, such as tire weights, fishing weights, lead foils, lead shot, batteries, solder, padlocks, and lead-containing dust. Other undesirable materials sometimes present in materials presented for recycling include ferrous articles, brass, copper, glass, and other heavy contaminants.
Such undesirable materials should be separated from the collected recycle material, at least partially, in order to minimize contaminants so as to reduce the required additions of virgin metal.
One approach to the separation of heavy constituents from light constituents in a comminuted mixture is disclosed in U.S. Pat. No. 4,853,112, which issued on Aug. 1, 1989, to Victor Brown. That patent shows an air classification apparatus for separating heavy from lighter components of comminuted municipal waste. However, the apparatus as disclosed involves a complicated air classifier that includes an air bypass arrangement that includes at least two flow control dampers that must be properly positioned for the system to operate effectively.
It is therefore an object of the present invention to provide a relatively simple, effective, and efficient apparatus for removing heavy, undesirable components from UBC.